The correct answer is B) The spaces shall be fitted with an approved fire or smoke detecting system. This is correct because under the applicable regulations, spaces on Ro-Ro vessels that are "specially suitable for vehicles" are required to be fitted with an approved fixed fire detection and fire alarm system. This helps to quickly detect any fire or smoke in those spaces, which can be critical for passenger safety on Ro-Ro vessels. The other answer choices are incorrect - A) is not required, C) fixed CO2 systems are permitted in those spaces, and D) is incorrect since only B is the true statement.